The study has the following aims: (1) To identify the characteristic patterns of interaction of families of poor, black, male compulsive heroin users; (2) To test out specific hypotheses about what is distinctive of these families' interaction. These hypotheses refer to the behavior of significant others that are currently maintaining the addicts' behavior and contemplate among others the possibilities of symmetrical and complementary behavior and of two and three generation conflicts; (3) To indicate how the family interaction (including the addict's participation in it) helps to encourage and maintain the addiction; (4) To develop and refine existing methodology for studying families; and (5) To develop new research hypotheses and specific guidelines for family therapy with heroin addicts. The study will involve 75 families. Thirty of these will be families in which at least one member is a heroin addict. The control groups will consist of 15 families of hospitalized schizophrenics, 15 families of hospitalized neurotics, and 15 families of high school achievers. All families will participate in an experimental session that will include three different tasks that will be performed by different sub-groups of the family and by the family as a whole. All family members will be reimbursed for their participation in the project. The interviews will be rated in order to identify the interactional patterns of families of heroin addicts.